Method

Pre-heat the oven to 220C/200C Fan/Gas 7. Boil the carrots for 5 minutes, then add the sweetcorn and peas and cook for 5 minutes or until all the vegetables are just tender. Drain.

Melt half the butter in a frying pan and cook the leek and mushrooms, stirring frequently, for 8-10 minutes or until they are tender.

Melt the remaining butter in a pan and stir in the flour. Remove from the heat and gradually whisk in the milk. Heat until boiling and thickened. Season well. Remove from the heat and stir in the cheese. Then add the mushroom and leek mixture with the pan juices and other vegetables.

Put the mixture into a pie dish (or four smaller pie dishes). Roll out the pastry to the thickness of a £1 coin. Cover the pie with the pastry, making a hole for the steam to escape.